ABOVE LAKE TAHOE -- Our single-file group of 14 snowmobilers _ some riding tandem, some solo _ followed the guide's hand signal and pulled over to the far right of the 10-foot-wide groomed track. Elevation: 9,000 feet.

We shut down our engines, climbed off the sleds and crunched through the fresh snow to a dramatic overlook. Visible about 3,000 feet below was most of vivid-blue Lake Tahoe. In the distance lay Emerald Bay, and to the left Genoa Peak, looking like a gigantic, dark jewel. We were at the top of the world, silenced by the natural wonders before us. For a few moments, only the wind made a sound.

That was one of the highlights of our two-hour, 25-mile snowmobile tour, which took us through parts of the Tahoe and the Toiyabe national forests, up around Spooner and Daggett summits and along parts of the Tahoe Rim Trail.

Another incredible scene had appeared a few minutes earlier, when our snowmobile pack wound through a heavily forested landscape that could have been the backdrop for a Brothers Grimm fairy tale. The towering, snow-and-ice-laden conifers hid the sun and sky, leaving a dim glow that cast a bluish color onto the rolling mini-hills of fresh snow.

"This is the most beautiful place on Earth," Debra Pearson said at the overlook, gazing over Lake Tahoe. She is a lobbyist from Scottsdale, Ariz., who was visiting the area with her husband, Craig, a taxidermist.

Nearby was the Adams family _ parents Ty and Tami, children Amanda and Brian _ from Charlotte, N.C.

What was the attraction?

"This is much prettier than home, with the lake," said Tami.

"The best part is the speed (of the sleds)," Brian chimed in.

"No, it's the breathtaking view," said Amanda.

We were part of the 9:30 a.m. Lakeview Tour, one of four daily outings into the Sierra Nevada backcountry led by the Zephyr Cove Snowmobile Center (ZCSC) in Zephyr Cove, Nev., one of the largest such operations in the United States.

If your adventurous nature is whetted for a taste of snowmobiling, a guided tour is the way to go. At South Lake Tahoe, two operators take novice and experienced snowmobilers into the mountains on a variety of tours _ including full-moon outings: the ZCSC and Lake Tahoe Adventures in Meyers, Calif.

In states such as Wisconsin, Michigan and Colorado, where residents survive long winters by being active, snowmobiling is a way of life, akin to what boating is in Florida.

But snowmobiling is an expensive and often tricky sport. For instance, layers of regulations and restrictions in California and Nevada make snowmobiling site-specific. Also, there's the expense: A new sled costs $6,000 to $12,000 (though most newcomers buy used sleds), and the trailer to haul it goes for another $2,000 to $3,000. Then there's the truck needed to haul the trailer, maintenance and insurance, registration fees, and the costs of fuel and proper outfitting for the rider. Suddenly, what begins as a weekend winter sport becomes a major investment.

"Outdoor recreation is expanding and people are looking for activities," said Jay Dobler, vice president of the California Nevada Snowmobile Association. Dobler began snowmobiling in 1971, owns eight sleds and works out of an office in Rancho Cordova, Calif.

"Snowmobiling is expensive, but it's addictive and people are willing to pay to do it. Also, it becomes a complete family activity."

What's another benefit?

"The social aspect is tremendous," Dobler said. "Families meet families and go on trips together. I'm planning a four-day trip myself with 15 others. People drop their jaws when you put them on a snowmobile and ride for 15 minutes to the top of a mountain with a 360-degree view," he said.

Not all is serene in the land of snow and ice, however. There is criticism of snowmobiling from numerous environmental groups _ some more mainstream than others _ mostly focused on the noise and air pollution the sleds create.

"The industry has really responded," Dobler said. "The sleds are quieter, cleaner and easier to ride. (Many of the new machines) exceed (federal) Environmental Protection Agency's standards."

As for the noise pollution disturbing cross-country skiers and snowshoers, Dobler's take reflects that of most snowmobilers: "The wilderness is big enough for everyone."

The Sierra Club would disagree.

"The club's position is that snowmobiles should not operate outside of designated areas, which is the same position we have on any off-road vehicle. Unfortunately, a small percentage of snowmobilers are in the habit of going where they want, not where they should," said Carol Tresner, former vice president and now the outings chairwoman of the Toiyabe Chapter of the Sierra Club. That chapter deals with parts of Northern California and Nevada, along the eastern Sierra.

"Snowmobilers keep encroaching into the wilderness areas, and the U.S. Forest Service doesn't have the manpower to police them," she said. "Snowmobiles smell terrible and make a lot of noise, and (snowmobiling) is not what we think of as an outdoors experience."

Snowmobile use has steadily grown in the past 10 years, to the point where regulation of it has become a national issue, ping-ponging around Washington, from the White House to Congress to the Department of the Interior. According to the latest figures, snowmobiling is allowed in 43 of the nation's 388 "National Park System units" scattered throughout 21 states.

One particularly controversial issue has been snowmobile use in Yellowstone and Grand Teton (in Wyoming) national parks, and the John D. Rockefeller Jr. Parkway, which connects the two. Last winter, for example, 24,049 people visited Yellowstone on snowmobiles.

"(All three parks) are currently operating under an interim plan (for snowmobile use) as we prepare an environmental impact report for public review later this year," said Al Nash, a Yellowstone spokesman.

Could that ultimately mean a snowmobile ban in the parks?

"That certainly has been proposed in the past," said Nash, who was quick to point out that "it's never been a situation where the snowmobiles go off track. They have always gone where cars go in the summer."

Snowmobiles are stable, powerful machines that can zip up the slope of a mountain, but, obviously, there's so much more to the sport than just jumping on one and heading out. Caution and experience are two basic requirements.

"More people are buying them, and we really hope the riders get the training because they're going into areas where there are all kinds of hazards," noted Steve Hale, a U.S. Forest Service recreation specialist at the Carson Ranger District in Carson City, Nev.

"There are rocks and stumps under the snow, and you can fall into creeks and rivers if you don't understand what snow bridges are," he said. "Unless you're traveling over a specifically designated, groomed area, it's like any other activity in the woods _ it's more risky than staying at home."

Other hazards include possible injury from collisions with other riders, or from hitting trees, and the threat of avalanches, Hale said. Plus, "Nowadays, the machines can get you farther away from your vehicle in a shorter period of time. If you go in beyond your ability, you can get stuck. So there are more search-and-rescue operations occurring."

The day before our trip, ZCSC general manager Chris Burke explained that the snowmobile center has special-use permits to operate tours out of two trailheads on U.S. Forest Service land.

"We maintain a 60-mile network of trails with $1 million worth of grooming equipment," he said.

Last winter, the center guided 28,000 visitors from around the world into the backcountry.

How fast would we be driving our snowmobiles on tomorrow's trip?

"The engines are not governed because you'll be going uphill in many places and you'll need the power," Burke said. "The only governor we have is our lead guide, who sets a safe speed. This is a scenic tour that happens to be on snowmobiles."

On the morning of our adventure, 72 men, women and children had assembled at the center, housed inside the Zephyr Cove Lodge. Many of them had been bused over from Harrah's Hotel-Casino; most of the others were part of tour groups. People chatted and laughed as they lined up to have their reservations verified, fill out waivers and pay fees. Those who were improperly dressed for the weather had to rent boots or clothing. Everyone was fitted for visored helmets.

Next, we boarded a bus for the eight-mile trip to the staging area _ a snow-covered meadow. There, we were greeted by mountain manager Tim Edison ("Welcome to my office!"), who divided the crowd into smaller, more manageable groups.

Our mini-caravan of eight adults and four children would be sandwiched between lead guide Alex Florez and tail guide Guy Mitchell. The idea was to stay within 10 to 20 feet of the rider in front of you and pass back any hand signals _ slow down, stop, kill the engine _ coming from Florez.

We gathered around a black SkiDoo sled and listened to Mitchell's orientation. He demonstrated how to start and stop the engine, and how the throttle and brakes work. No shifting of gears is involved.

"See these toggle switches?" Mitchell said. "The one on the left is for the rocket launcher, the one on the right is for the machine gun. This one is for the parachute, but don't worry about that. No, really, they control the hand-grip warmers.

"If you tip over, keep your feet on the running boards. That way, the machine will take the fall, not you. If you tip over, we'll laugh at you and help you up. One reason you might tip over is by not leaning into your turns. If you turn the handlebars left, you want to lean left. Same with turning right. The more you lean, the less you'll have to muscle up front."

That was it. We started our engines with a collective roar and took off, climbing and twisting through a winter wonderland of groomed trails. Though the ride was bumpy at times, there was no slip 'n' slide and at no point was there any feeling of jeopardy.

The drill was like this: Turn left, lean left; turn right, lean right; accelerate uphill, let off on the thumb throttle downhill. Forest and snowbanks on the left and right, mountain peaks on the horizon. What a rush! We reached speeds of up to 25 mph, which felt more like 70 to this first-time rider.

I had a pretty good feel for the sled after a half-hour, about the time we took a brief break for a head count. Later, I cheated and stood up on the running boards, steering from that position, hoping to increase the thrill factor. The overall buzz was so exhilarating that I badly wanted to leave the trail, mash the throttle to the max and zoom up and over the nearest virgin hillside.

Hey, dudes, eat my snow! I don't think I was the only one with such a potentially dangerous fantasy.

About three-quarters into the ride, we converged with other groups of snowmobilers in an aspen-studded meadow and were served cups of steaming hot chocolate. The crowd was jazzed and chatted nonstop about the ride and the views.

Though the day was overcast, one thing was crystal-clear: I'd mount up again in a heartbeat, only without the standing-up part. Well, not at first, anyway.

(The Sacramento Bee's Allen Pierleoni can be reached at (916) 321-1128 or apierleoni(at)sacbee.com.)